Optical trackball



FIG. 1 is a perspective view of a mouse showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a left side view, the right side view is a mirror image thereof;

FIG. 5 is a rear view thereof; and,

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a optical trackball, as shown and described. 